Particle dispersion La1-xSrxMnO3 compact thermal control coating and preparation method thereof, aviation workpiece and spacecraft

Abstract

The invention provides a particle dispersion La1-xSrxMnO3 compact thermal control coating, a preparation method thereof, an aviation workpiece and a spacecraft, and relates to the field of aerospace. The preparation method comprises the steps that a substrate is electroplated through electroplating liquid, and the electroplated substrate is prepared; and the electroplated substrate is subjected to high-temperature roasting, and the particle dispersion La < 1-x > Sr < x > MnO < 3 > compact thermal control coating is obtained. The electroplating solution comprises La < 3 + > ions, Mn < 4 + > ions and micron-sized SrO powder; wherein x in the La < 1-x > Sr < x > MnO < 3 > is 0.2 to 0.8. The preparation method is specially suitable for preparation of irregular workpiece coatings.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and more particularly to a particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating and preparation method thereof, aviation workpiece and spacecraft. Background Art

[0002] As the development of small spacecraft accelerates, the problem of temperature control of its equipment also arises. Considering the small size and light weight of such spacecraft, the temperature condition is mainly provided by passive thermal control system, the main element of which is thermal control coating (TCC) applied on the body and equipment. Therefore, the development of new thermal control coating based on new materials and their manufacturing and application processes is an urgent task of space materials science.

[0003] Thermal control coatings mainly control the surface temperature of coatings by changing the two parameters of solar absorptivity and infrared emissivity on the surface of objects. They are one of the most commonly used thermal control materials in spacecraft thermal control systems. When a spacecraft reaches aphelion, the external solar radiation energy decreases, and the heat source mainly comes from internal components. Therefore, the temperature of the outer surface of the equipment is low, and the temperature of the inner surface is high, resulting in the problem of slow external heating and slow internal cooling of the material. When the spacecraft reaches perihelion, its heat source mainly comes from external space radiation, so the temperature of the outer surface of the equipment is high, resulting in rapid external heating of the material. The thermal control coating uses the surface thermophysical properties of the spacecraft to effectively control the temperature of the spacecraft during radiation heat exchange. Ultimately, during the internal and external heat exchange process, the operating temperature of internal equipment and instruments does not exceed the specified range, ensuring the normal operation of the spacecraft.

[0004] At present, the more advanced TCC ceramic coating material is La 1-x Sr x MnO 3 (LSM) material system, the LSM coating system has a hemispherical emissivity of up to 0.6 or above in the range of 100μm to 300μm, stable infrared radiation performance, and excellent reflective heat insulation capabilities; it is generally prepared by atmospheric plasma spraying, sol-gel, and physical vapor deposition processes. The LSM material prepared by atmospheric plasma spraying has poor fracture toughness when deposited into a coating, and the coating is loose and porous inside, which is prone to failure during service and cannot meet the use requirements; the LSM coating is prepared by the sol-gel method, and its deposition efficiency is not high, and it cannot be used for composite production tasks; the LSM coating is prepared by the physical vapor deposition method, and its structure is mostly a columnar crystal structure. This structure has many longitudinal cracks, which has a negative impact on the intelligent thermal control coating.

[0005] Therefore, how to obtain intelligent thermal control coatings with higher density and higher fracture toughness is a problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of this application is to provide a particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating and preparation method thereof, aviation workpiece and spacecraft are used to solve the above problems.

[0007] To achieve the above objectives, the present application provides a particle dispersion La 1-x Sr x MnO 3 A method for preparing a dense thermal control coating, comprising:

[0008] Electroplating the substrate with an electroplating solution to obtain an electroplated substrate;

[0009] The electroplated substrate is calcined at high temperature to obtain the particle dispersed La 1-x Sr x MnO 3 Dense thermal control coating;

[0010] The plating solution includes La 3+ Ion, Mn 4+ Ionic and micron-sized SrO powders;

[0011] Among them, La 1-x Sr x MnO 3 where x is 0.2-0.8.

[0012] Optionally, the particle dispersion La 1-x Sr x MnO 3 The method for preparing a dense thermal control coating satisfies at least one of the following conditions:

[0013] A. The Dv10 of the micron-sized SrO powder is 1 μm-8 μm;

[0014] B. The Dv50 of the micron-sized SrO powder is 6 μm-12 μm;

[0015] C. The Dv90 of the micron-sized SrO powder is 10 μm-20 μm;

[0016] D. The mass content of the micron-sized SrO powder in the electroplating solution is 50 g / L-150 g / L;

[0017] E. La in the plating solution 3+ The concentration of ions is 0.5mol / L-1.0mol / L;

[0018] F. The Mn in the electroplating solution4+ The concentration of ions is 1mol / L-1.5mol / L.

[0019] Optionally, the particle dispersion La 1-x Sr x MnO 3 The method for preparing a dense thermal control coating satisfies at least one of the following conditions:

[0020] A. The current density of the electroplating is 1.5A / dm 2 -2.5A / dm 2 , temperature is 40℃-45℃, time is 3h-6h;

[0021] B. The electroplating process is also intermittently stirred, the frequency of the intermittent stirring is 1min-1.5min, the stirring stop time is 0.5min-1min, and the stirring speed is 400r / min-700r / min;

[0022] C. The substrate also rotates at a speed of 0.5° / s-1.5° / s.

[0023] Optionally, the high temperature calcination temperature is 600°C-900°C, and the insulation time is 2h-7h.

[0024] Optionally, the particle dispersion La 1-x Sr x MnO 3 The preparation method of the dense thermal control coating satisfies at least one of the following conditions:

[0025] A. The density of the micron-sized SrO powder is 50%-70%;

[0026] B. The micron-sized SrO powder includes a spherical shape;

[0027] C. The method for preparing the micron-sized SrO powder comprises: spray drying the SrO raw material to obtain the powder.

[0028] Optionally, the nozzle speed of the spray drying is 40Hz-45Hz, the inlet temperature is 200℃-300℃, the outlet temperature is 50℃-100℃, and the peristaltic pump speed is 15rpm-25rpm.

[0029] In a second aspect, the present application provides a particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating, composed of the particles dispersed La 1-x Sr x MnO 3The dense thermal control coating is prepared by a preparation method.

[0030] Optionally, the coating has a thickness of 100 μm-300 μm.

[0031] The third aspect of the present application provides an aerospace workpiece, including the particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating.

[0032] A fourth aspect of the present application provides a spacecraft, comprising the aerospace artifact described above.

[0033] Compared with the prior art, the beneficial effects of this application include:

[0034] The particle dispersion La 1-x Sr x MnO 3 A method for preparing a dense thermal control coating, comprising micron-sized SrO powder, La 3+ Ions and Mn 4+ The substrate is electroplated with an ion electroplating solution to form an electroplated substrate in which SrO oxide powder is embedded in the LaMn alloy. The LaMn alloy is then subjected to a high-temperature heat treatment process to form an oxide LaMn oxide, and the SrO powder is interdiffused with the La and Mn alloy layers to achieve chemical composition regulation. This preparation method is particularly suitable for the preparation of coatings for irregular workpieces.

[0035] The particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating, the coating has uniform thickness and dense structure, with SrO oxide dispersed particles inside. SrO oxide dispersed particles are dispersed in particles. 1-x Sr x MnO 3In the dense thermal control coating, SrO oxide particles are dispersed as dispersed phases and are evenly distributed in the LSM coating to form a solid solution or solid interface, thereby forming a dispersed strengthening structure, so that the presence of SrO oxide particles as fine particles can effectively prevent the expansion of cracks, and the cracks will encounter the obstruction of SrO oxide particles during the propagation process, resulting in a slowdown in the crack expansion rate, thereby improving the toughness of the material; secondly, the presence of SrO oxide particles can help disperse the internal stress of the coating. When the coating is subjected to stress, SrO particles can relieve local stress concentration by increasing local dislocation slip and plastic deformation, thereby reducing the probability of crack generation; at the same time, these particles have high hardness and strength, and can guide cracks to propagate along the interface between particles, reducing the direct crack propagation path, thereby enhancing the overall fracture toughness of the coating; among them, SrO oxide dispersed particles and LaMn oxide, under high temperature conditions, SrO can react with LaMnO 3 Reaction occurs to generate La 1-x Sr x MnO 3 This reaction usually causes Sr ions to partially replace La ions, thereby adjusting the chemical composition and crystal structure of the material. 1-x Sr x MnO 3 It has a higher hemispherical emissivity, which is very important for optimizing the performance of smart thermal control coatings.

[0036] The aviation workpiece and spacecraft provided by the present application have uniform coating and good service performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0038] Figure 1 This is a SEM image of the micron-sized SrO powder provided in Example 1;

[0039] Figure 2 The particle dispersion La provided in Example 1 1-x Sr x MnO 3 SEM image of the dense thermal control coating. DETAILED DESCRIPTION

[0040] As used herein:

[0041] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0043] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0044] In these examples, parts and percentages are by mass unless otherwise indicated.

[0045] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0046] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0047] The present application provides a particle dispersion La 1-x Sr x MnO3 A method for preparing a dense thermal control coating, comprising:

[0048] Electroplating the substrate with an electroplating solution to obtain an electroplated substrate;

[0049] The electroplated substrate is calcined at high temperature to obtain the particle dispersed La 1-x Sr x MnO 3 Dense thermal control coating;

[0050] The plating solution includes La 3+ Ion, Mn 4+ Ionic and micron-sized SrO powders;

[0051] It should be noted that the Sr element is relatively active. When Sr is dissolved in a solution, it can react with water at room temperature to generate strontium hydroxide and hydrogen, making electroplating deposition impossible. Therefore, the use of SrO powder can avoid the problem of poor electroplating deposition effect of Sr-containing solutions.

[0052] In some embodiments, La 3+ The source of ions includes, but is not limited to, one or more of lanthanum chloride, lanthanum sulfate, and lanthanum carbonate;

[0053] In some embodiments, Mn 4+ The source of ions includes, but is not limited to, one or more of potassium permanganate, manganese hydrogen peroxide, and sodium manganese sulfate;

[0054] Among them, La 1-x Sr x MnO 3 where x is 0.2-0.8.

[0055] Optionally, x may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or any value between 0.2 and 0.8.

[0056] In some embodiments, the particle dispersion La 1-x Sr x MnO 3 The method for preparing a dense thermal control coating satisfies at least one of the following conditions:

[0057] A. The Dv10 of the micron-sized SrO powder is 1 μm-8 μm;

[0058] Optionally, the Dv10 of the micron-sized SrO powder may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or any value between 1 μm and 8 μm;

[0059] B. The Dv50 of the micron-sized SrO powder is 6 μm-12 μm;

[0060] Optionally, the Dv50 of the micron-sized SrO powder may be 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm or any value between 6 μm and 12 μm;

[0061] C. The Dv90 of the micron-sized SrO powder is 10 μm-20 μm;

[0062] Optionally, the Dv90 of the micron-sized SrO powder may be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or any value between 10 μm and 20 μm;

[0063] D. The mass content of the micron-sized SrO powder in the electroplating solution is 50 g / L-150 g / L;

[0064] Optionally, the mass content of micron-sized SrO powder in the electroplating solution may be 50 g / L, 100 g / L, 150 g / L, or any value between 50 g / L and 150 g / L;

[0065] It should be noted that due to the high density of SrO powder, 3+ and Mn 4+ When electrodeposited in a solution, there are problems such as low deposition efficiency, so it is necessary to control the particle size. When the powder particle size is too large and the mass is too much, the SrO powder sinks to the bottom, reducing the deposition efficiency; when the powder particle size is too small and the mass is too little, the powder deposition is too little, and the thermal control coating cannot be used.

[0066] E. La in the plating solution 3+ The concentration of ions is 0.5mol / L-1.0mol / L;

[0067] Optionally, La in the plating solution 3+ The concentration of the ions may be 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L or any value between 0.5 mol / L and 1.0 mol / L;

[0068] F. The Mn in the electroplating solution 4+ The concentration of ions is 1mol / L-1.5mol / L.

[0069] Optionally, Mn in the plating solution 4+The concentration of the ions may be 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L or any value between 1 mol / L and 1.5 mol / L.

[0070] It should be noted that Mn 4+ The ion concentration is too high, so the substrate deposits too much manganese metal coating, resulting in the substrate being wrapped by manganese alloy and unable to form La 1-x Sr x MnO 3 structure, and cannot play the role of thermal control coating, Mn 4+ Too little ion concentration results in a weak electrophoresis effect and low SrO powder deposition efficiency.

[0071] In some embodiments, the particle dispersion La 1-x Sr x MnO 3 The method for preparing a dense thermal control coating satisfies at least one of the following conditions:

[0072] A. The current density of the electroplating is 1.5A / dm 2 -2.5A / dm 2 , temperature is 40℃-45℃, time is 3h-6h;

[0073] Optionally, the current density of the electroplating can be 1.5A / dm 2 , 2A / dm 2 , 2.5A / dm 2 or 1.5A / dm 2 -2.5A / dm 2 The temperature can be 40°C, 41°C, 42°C, 43°C, 44°C, 45°C or any value between 40°C and 45°C, and the time can be 3h, 4h, 5h, 6h or any value between 3h and 6h;

[0074] B. The electroplating process is also intermittently stirred, the frequency of the intermittent stirring is 1min-1.5min, the stirring stop time is 0.5min-1min, and the stirring speed is 400r / min-700r / min;

[0075] Optionally, the frequency of intermittent stirring is that the stirring time can be 1 min, 1.1 min, 1.2 min, 1.3 min, 1.4 min, 1.5 min or any value between 1 min and 1.5 min, the time to stop stirring can be 0.5 min, 0.6 min, 0.7 min, 0.8 min, 0.9 min, 1 min or any value between 0.5 min and 1 min, and the stirring speed can be 400 r / min, 500 r / min, 600 r / min, 700 r / min or any value between 400 r / min and 700 r / min;

[0076] It should be noted that when stirring is continued during the electroplating process, the micron-sized SrO powder will be in motion all the time, so that the amount of micron-sized SrO powder settling on the substrate will decrease. When stirring is not performed during the electroplating process, the micron-sized SrO powder will settle quickly, resulting in an increase in the amount of micron-sized SrO powder in the substrate. Therefore, it is necessary to control intermittent stirring during the electroplating process to control the amount of micron-sized SrO powder settling.

[0077] C. The substrate also rotates at a speed of 0.5° / s-1.5° / s.

[0078] Optionally, the rotation speed may be 0.5° / s, 1° / s, 1.5° / s or any value between 0.5° / s and 1.5° / s.

[0079] It should be noted that the uniform self-rotation of the substrate can help the electroplating solution to be more evenly distributed on the various surfaces of the substrate. During the rotation process, different surfaces of the substrate will continuously contact the electroplating solution, forming a stable flow and shear force, which helps the uniform sedimentation and electroplating of various surfaces of the substrate, thereby obtaining a more uniform coating. Especially when electroplating a large area, the self-rotation of the substrate can avoid uneven deposition of ions in the electroplating solution and ensure the uniformity of the coating.

[0080] In some embodiments, the high temperature calcination temperature is 600° C.-900° C., and the holding time is 2 h-7 h.

[0081] Optionally, the temperature of high temperature calcination can be 600°C, 700°C, 800°C, 900°C or any value between 600°C and 900°C, and the insulation time can be 2h, 3h, 4h, 5h, 6h, 7h or any value between 2h and 7h.

[0082] It should be noted that if the high-temperature calcination temperature is too low and the time is too short, the SrO powder in the coating and the La and Mn alloy layers will not be able to fully dissolve and diffuse; if the temperature is too high and the time is too long, the SrO powder in the coating and the La and Mn alloy layers will not be able to fully dissolve and diffuse; it will cause the base alloy to overheat and cause deformation and failure.

[0083] In some embodiments, the particle dispersion La 1-x Sr x MnO 3 The preparation method of the dense thermal control coating satisfies at least one of the following conditions:

[0084] A. The density of the micron-sized SrO powder is 50%-70%;

[0085] It should be noted that as a hard oxide, the density of SrO itself determines the hardness of the LSM coating. Its particles can be embedded in the substrate surface during the electroplating process to form a dispersion-strengthened coating. Micron-sized dense SrO powder can increase the density of the coating, reduce pores and voids, and improve the hardness and wear resistance of the coating. Dense SrO powder helps to form a uniform distribution in the electroplating solution. Due to the high density of the powder, the space between the particles is small, reducing the risk of uneven deposition or local over-deposition during the electroplating process. Uniform particle distribution can ensure the consistency of coating thickness and reduce the occurrence of surface defects.

[0086] B. The micron-sized SrO powder includes a spherical shape;

[0087] C. The method for preparing the micron-sized SrO powder comprises: spray drying the SrO raw material to obtain the powder.

[0088] In some embodiments, the ball-milled SrO slurry is introduced into the inlet of a spray granulator through a peristaltic pump for spray granulation to obtain micron-sized SrO powder. The micron-sized SrO powder after spray drying has a high density, which can increase the density of the coating, reduce pores and voids, and improve the hardness and wear resistance of the coating.

[0089] In some embodiments, the spray drying nozzle speed is 40 Hz-45 Hz, the inlet temperature is 200° C.-300° C., the outlet temperature is 50° C.-100° C., and the peristaltic pump speed is 15 rpm-25 rpm.

[0090] Optionally, the nozzle speed of the spray drying can be 40Hz, 41Hz, 42Hz, 43Hz, 44Hz, 45Hz or any value between 40Hz-45Hz, the inlet temperature can be 200℃, 250℃, 300℃ or any value between 200℃-300℃, the outlet temperature can be 50℃, 60℃, 70℃, 80℃, 90℃, 100℃ or any value between 50℃-100℃, and the peristaltic pump speed can be 15rpm, 10rpm, 25rpm or any value between 15rpm-25rpm.

[0091] It should be noted that the spray drying process can control the powder particle size. If the nozzle speed is too high and the peristaltic pump speed is too low, the powder particle size will be too fine; if the nozzle speed is too low and the peristaltic pump speed is too high, the powder particle size will be too coarse.

[0092] In a second aspect, the present application provides a particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating, composed of the particles dispersed La 1-x Sr x MnO 3 The dense thermal control coating is prepared by a preparation method.

[0093] It should be noted that the particle dispersion La 1-x Sr x MnO 3 The thickness of the dense thermal control coating can be adjusted according to actual conditions.

[0094] In some embodiments, the coating has a thickness of 100 μm-300 μm.

[0095] Optionally, the thickness of the coating may be 100 μm, 150 μm, 200 μm, 250 μm, 300 μm or any value between 100 μm and 300 μm.

[0096] The third aspect of the present application provides an aerospace workpiece, including the particle dispersion La 1-x Sr x MnO 3 Dense thermal control coating.

[0097] A fourth aspect of the present application provides a spacecraft, comprising the aerospace artifact described above.

[0098] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0099] Example 1

[0100] This embodiment provides a particle dispersion La 1-x Sr x MnO 3 (x is 0.5) The preparation method of the dense thermal control coating, the specific steps are as follows:

[0101] S1: The SrO slurry after ball milling was introduced into the inlet of the spray granulator through a peristaltic pump for spray granulation. The nozzle speed was controlled at 43Hz, the inlet temperature of the granulation tower was 280℃, the outlet temperature was 70℃, and the peristaltic pump speed was 20rpm to obtain spherical micron-sized SrO powder. The specific SEM is as follows Figure 1 As shown, the Dv10 of the micron-sized SrO powder is 1μm-8μm, the Dv50 is 6μm-12μm, and the Dv90 is 10μm-20μm; the density is 60%;

[0102] S2: LaCl 3 and KMnO 4 The solution is mixed with the micron-sized SrO powder prepared above to obtain an electroplating solution; wherein the mass content of the micron-sized SrO powder in the electroplating solution is 100 g / L, La 3+ The concentration of ions is 0.8 mol / L, Mn 4+ The concentration of ions is 1.2 mol / L;

[0103] S3: The sample substrate GH4169 is used as the electroplating cathode and immersed in the electroplating solution. The electroplating substrate is bound by a rotor and rotated at a constant speed of 1.0° / s. The electroplating is carried out under constant current conditions with a current density of 2.0A / dm 2 , the temperature is 45°C, the time is 5h, and intermittent stirring is performed during the electroplating process. The frequency of intermittent stirring is 1min, the stopping time is 0.5min, and the stirring speed is 500r / min to obtain the substrate after electroplating;

[0104] S4: The electroplated substrate is subjected to high temperature calcination at a temperature of 900°C for 5 hours to obtain a particle dispersion of La 1-x Sr x MnO 3 Dense thermal control coating, thickness is 200μm, specific SEM as follows Figure 2 shown.

[0105] Example 2

[0106] This embodiment provides a particle dispersion La 1-x Sr x MnO 3 (x is 0.3) The preparation method of the dense thermal control coating, the specific steps are as follows:

[0107] S1: The SrO slurry after ball milling was introduced into the inlet of the spray granulator through a peristaltic pump for spray granulation. The nozzle speed was controlled at 43Hz, the inlet temperature of the granulation tower was 280℃, the outlet temperature was 70℃, and the peristaltic pump speed was 20rpm to obtain spherical micron-sized SrO powder. The specific SEM is as follows Figure 1As shown, the Dv10 of the micron-sized SrO powder is 1μm-8μm, the Dv50 is 6μm-12μm, and the Dv90 is 10μm-20μm; the density is 60%;

[0108] S2: LaCl 3 and KMnO 4 The solution is mixed with the micron-sized SrO powder prepared above to obtain an electroplating solution; wherein the mass content of the micron-sized SrO powder in the electroplating solution is 50 g / L, and La 3+ The concentration of ions is 1.0 mol / L, Mn 4+ The concentration of ions is 1.2 mol / L;

[0109] S3: The sample substrate GH4169 is used as the electroplating cathode and immersed in the electroplating solution. The electroplating substrate is bound by a rotor and rotated at a constant speed of 1.0° / s. The electroplating is carried out under constant current conditions with a current density of 2.0A / dm 2 , the temperature is 45°C, the time is 5h, and intermittent stirring is performed during the electroplating process. The frequency of intermittent stirring is 1min, the stopping time is 0.5min, and the stirring speed is 500r / min to obtain the substrate after electroplating;

[0110] S4: The electroplated substrate is subjected to high temperature calcination at a temperature of 900°C for 5 hours to obtain a particle dispersion of La 1-x Sr x MnO 3 Dense thermal control coating with a thickness of 200μm.

[0111] Example 3

[0112] This embodiment provides a particle dispersion La 1-x Sr x MnO 3 (x is 0.7) The preparation method of the dense thermal control coating, the specific steps are as follows:

[0113] S1: The SrO slurry after ball milling was introduced into the inlet of the spray granulator through a peristaltic pump for spray granulation. The nozzle speed was controlled at 43Hz, the inlet temperature of the granulation tower was 280℃, the outlet temperature was 70℃, and the peristaltic pump speed was 20rpm to obtain spherical micron-sized SrO powder. The specific SEM is as follows Figure 1 As shown, the Dv10 of the micron-sized SrO powder is 1μm-8μm, the Dv50 is 6μm-12μm, and the Dv90 is 10μm-20μm; the density is 60%;

[0114] S2: LaCl 3 and KMnO 4The solution is mixed with the micron-sized SrO powder prepared above to obtain an electroplating solution; wherein the mass content of the micron-sized SrO powder in the electroplating solution is 150 g / L, and La 3+ The concentration of ions is 0.5 mol / L, Mn 4+ The concentration of ions is 1.2 mol / L;

[0115] S3: The sample substrate GH4169 is used as the electroplating cathode and immersed in the electroplating solution. The electroplating substrate is bound by a rotor and rotated at a constant speed of 1.0° / s. The electroplating is carried out under constant current conditions with a current density of 2.0A / dm 2 , the temperature is 45°C, the time is 5h, and intermittent stirring is performed during the electroplating process. The frequency of intermittent stirring is 1min, the stopping time is 0.5min, and the stirring speed is 500r / min to obtain the substrate after electroplating;

[0116] S4: The electroplated substrate is subjected to high temperature calcination at a temperature of 900°C for 5 hours to obtain a particle dispersion of La 1-x Sr x MnO 3 Dense thermal control coating with a thickness of 200μm.

[0117] Comparative Example 1

[0118] The difference from Example 1 is that the micron-sized SrO powder in the electroplating solution is replaced by SrCl 2 Solution.

[0119] Comparative Example 2

[0120] The difference from Example 1 is that the micron-sized SrO powder in the electroplating solution of this comparative example has a Dv10 of 10 μm-18 μm, a Dv50 of 19 μm-28 μm, and a Dv90 of 28 μm-39 μm.

[0121] Comparative Example 3

[0122] The difference from Example 1 is that the micron-sized SrO powder in the electroplating solution of this comparative example has a Dv10 of 0.1 μm-0.8 μm, a Dv50 of 1 μm-5 μm, and a Dv90 of 6 μm-10 μm.

[0123] Comparative Example 4

[0124] The difference from Example 1 is that the mass content of the micron-sized SrO powder in the electroplating solution of this comparative example is 20 g / L.

[0125] Comparative Example 5

[0126] The difference from Example 1 is that the La in the plating solution of this comparative example is 3+The concentration of ions is 0.2 mol / L.

[0127] Comparative Example 6

[0128] The difference from Example 1 is that the Mn in the plating solution of this comparative example is 4+ The concentration of ions is 0.5 mol / L.

[0129] Comparative Example 7

[0130] The difference from Example 1 is that this comparative example does not perform high-temperature calcination after the electroplating is completed.

[0131] The coatings prepared in the above examples and comparative examples were subjected to performance tests, mainly including fracture toughness test, reflective heat insulation performance test, etc. The specific test results are shown in Table 1.

[0132] Among them, the fracture toughness test method is: "ASTM E1820-23b Standard Test Method for Fracture Toughness Measurement".

[0133] The method for hemispherical emissivity test is: "GJB 2502.3-2015 Spacecraft Thermal Control Coating Test Method Part 3".

[0134] Table 1 Performance test

[0135] Test samples Fracture toughness test Hemispherical emissivity test Example 1 <![CDATA[23MPa·m 1 / 2 ]]> 0.751 Example 2 <![CDATA[15MPa·m 1 / 2 ]]> 0.813 Example 3 <![CDATA[28MPa·m 1 / 2 ]]> 0.625 Comparative Example 1 <![CDATA[6MPa·m 1 / 2 ]]> 0.679 Comparative Example 2 <![CDATA[14MPa·m 1 / 2 ]]> 0.457 Comparative Example 3 <![CDATA[7MPam 1 / 2 ]]> 0.698 Comparative Example 4 <![CDATA[16MPa·m 1 / 2 ]]> 0.697 Comparative Example 5 <![CDATA[27MPa·m 1 / 2 ]]> 0.394 Comparative Example 6 <![CDATA[24MPa·m 1 / 2 ]]> 0.368 Comparative Example 7 <![CDATA[10MPa·m 1 / 2 ]]> 0.264

[0136] analyze:

[0137] It can be seen from Table 1 that the particle dispersion La 1-x Sr x MnO 3 The performance tests of the dense thermal control coating are all better than those of the coating prepared in the comparative example.

[0138] It can be seen from Comparative Example 1 that even if the electroplating method is used and an electroplating solution containing Sr is provided, the particle dispersion La provided in the present application cannot be achieved. 1-x Sr x MnO 3 The effect of dense thermal control coating is that when Sr is dissolved in the solution, it can react with water at room temperature to generate strontium hydroxide and hydrogen, making electroplating deposition impossible.

[0139] It can be seen from Comparative Examples 2 and 3 that when the particle size of the micron-sized SrO powder does not meet the requirements of Dv10 of 1 μm-8 μm, Dv50 of 6 μm-12 μm, and Dv90 of 10 μm-20 μm, excessively large particles may cause an uneven structure on the coating surface, reducing the hardness and wear resistance of the coating. Excessively small particles may cause the dispersion strengthening structure of the coating to be destroyed, which may reduce the fracture toughness of the coating and affect its coating performance.

[0140] From Comparative Examples 4, 5, and 6, it can be seen that when the micron-sized SrO powder and La 3+ Ions and Mn 4+ When the ion concentration is not within the range specified in this application, it will cause particle dispersion La 1-x Sr x MnO 3 The composition of the dense thermal control coating deviates, causing its hemispherical emissivity to decrease and making the thermal control coating lose its function.

[0141] It can be seen from Comparative Example 7 that failure to perform high-temperature calcination after electroplating will result in the alloy coating being unable to oxidize and solid-dissolve, which reduces its hemispherical emissivity and loses the function of the thermal control coating.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0143] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A particle dispersion La 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: include: Electroplating the substrate with an electroplating solution to obtain an electroplated substrate; The electroplated substrate is calcined at high temperature to obtain the particle dispersed La 1-x Sr x MnO3 dense thermal control coating; The plating solution includes La 3+ Ion, Mn 4+ Ionic and micron-sized SrO powders; Among them, La 1-x Sr x The x in MnO3 is 0.2-0.

8.

2. The particle dispersion La according to claim 1 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: At least one of the following conditions is met: A. The Dv10 of the micron-sized SrO powder is 1 μm-8 μm; B. The Dv50 of the micron-sized SrO powder is 6 μm-12 μm; C. The Dv90 of the micron-sized SrO powder is 10 μm-20 μm; D. The mass content of the micron-sized SrO powder in the electroplating solution is 50 g / L-150 g / L; E. La in the plating solution 3+ The concentration of ions is 0.5mol / L-1.0mol / L; F. The Mn in the electroplating solution 4+ The concentration of ions is 1mol / L-1.5mol / L.

3. The particle dispersion La according to claim 1 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: At least one of the following conditions is met: A. The current density of the electroplating is 1.5A / dm 2 -2.5A / dm 2 , temperature is 40℃-45℃, time is 3h-6h; B. The electroplating process is also intermittently stirred, the frequency of the intermittent stirring is 1min-1.5min, the stirring stop time is 0.5min-1min, and the stirring speed is 400r / min-700r / min; C. The substrate also rotates at a speed of 0.5° / s-1.5° / s.

4. The particle dispersion La according to claim 1 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: The high temperature calcination temperature is 600° C.-900° C., and the heat preservation time is 2 h-7 h.

5. The particle dispersion La according to any one of claims 1 to 4 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: At least one of the following conditions is met: A. The density of the micron-sized SrO powder is 50%-70%; B. The micron-sized SrO powder includes a spherical shape; C. The method for preparing the micron-sized SrO powder comprises: spray drying the SrO raw material to obtain the powder.

6. The particle dispersion La according to claim 5 1-x Sr x The method for preparing a MnO3 dense thermal control coating is characterized in that: The nozzle speed of the spray drying is 40Hz-45Hz, the inlet temperature is 200℃-300℃, the outlet temperature is 50℃-100℃, and the peristaltic pump speed is 15rpm-25rpm.

7. A particle dispersion La 1-x Sr x MnO3 dense thermal control coating, characterized in that: The particle dispersion La according to any one of claims 1 to 6 1-x Sr x The MnO3 dense thermal control coating is prepared by a preparation method.

8. The particle dispersion La according to claim 7 1-x Sr x MnO3 dense thermal control coating, characterized in that: The coating has a thickness of 100 μm-300 μm.

9. An aerospace workpiece, characterized in that: The particle dispersion La according to claim 7 or 8 1-x Sr x MnO3 dense thermal control coating.

10. A spacecraft, characterized in that: Including the aerospace workpiece as described in claim 9.

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